Wednesday, January 11, 2006

GPS Digital Cameras

I was listening to the podcast of an episode of On Point in which they were talking about the "geospatial web" where information is tagged and distributed by information. There's been a lot talked and written about this topic, especially with all the great Google Maps mashups, Google Earth, and the competing Microsoft and Yahoo products.

I was talking to Raudel the other day, and he was thinking about improving his motorcyle road trip webpage by putting together an online photo album that geo-referenced images on Google Maps. He has to backfill the coordinates with his GPS track, though, because like most cameras, his doesn't have built in GPS. Wouldn't it be cool if they did? After all, cell phones have GPS, why not cameras? So far, the only one I can find is the Ricoh Caplio Pro G3 but even its GPS is an external card that plugs in. There are a lot of posts on blogs out there saying this same thing, so my guess is that it's just a matter of time, as development cycles do take a little time.

There are a couple drawbacks to GPS, in particular it will not always work inside buildings. But as long as it is continuously in contact with the GPS, even when it's "off", it could always just use its last known position.

What would be really cool is if the camera could also know which direction it was pointed. GPS can't tell you that, but if you could shrink a magnetometer enough to fit in a camera, you could get your magnetic heading. Unfortunately, the only ones I can find are at minimum 0.75" by 1.5". Perhaps an opportunity for MEMS manufacturers? But you also have to deal with magnetic interference, which in a compact device like a camera could be difficult.

Or, an alternative would be some variation on a direction finder. In the aviation world, there are old navigation devices called Automatic Direction Finders, or ADF. These point towards a non-directional beacon and give you your bearing to the station. In flight, they're not as useful as a VOR because of crosswinds. I've never used one before, and it's hard to find planes that have them anymore. But, using the principle of the ADF, you might be able to determine your heading.

If you tune in to just one station, you know your relative bearing to that station, i.e. it's 30 degrees to the left of straight ahead. If you know its position and your own position from GPS, then you can calculate the true bearing. Say, the station 270 degree (due West) of us. If the station is 30 degrees to the left of straight ahead, then we must be pointing at 300 degrees. Or, if you tune to two stations, you can skip the GPS and triangulate your position. Now, using aviation NDBs on the ground isn't really an option, but you could certainly use TV broadcast towers, cell phone towers, WiFi hotspots, or anything else that broadcasts from a fixed position. In fact, some cell phones triangulate position from nearby towers. Just add in relative bearing, and you've got yourself a heading.

Now, the next trick is to figure out the vertical angle. Perhaps a miniature accelerometer? Hard to think that would work for a device that would get moved and tossed about as much as a camera, but of course you usually try to hold the camera steady when taking a picture. It might just work...

1 Comments:

At 3:31 PM, Blogger Thomas said...

wow.. you need some new hobbies or perhaps a girlfriend

 

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